scholarly journals Investigation of Optimum Grinding Condition Using cBN Electroplated End-Mill for CFRP Machining

2021 ◽  
Vol 15 (1) ◽  
pp. 4-16
Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  

Recently, carbon fiber reinforced plastics (CFRP) have been used in various applications such as airplanes and automobiles. In CFRP molding, there are unnecessary portions on the outer area. Therefore, a machining process is required to remove them. Cutting and grinding are conventionally used in the finish machining of CFRPs. End-milling allows the removal of most of these portions. However, uncut fibers easily occur during end-milling. In contrast, a precise machined surface and edge are easily obtained using a grinding tool. Therefore, this research has developed a novel cubic boron nitride (cBN) electroplated end-mill that combines an end-mill and a grinding tool. This is a versatile tool that can cut and grind CFRPs by changing the direction of rotation of the tool. In this study, the effectiveness of the developed tool is investigated. First, the developed tool machined the CFRP by side milling. Consequently, cBN abrasives that were fixed on the outer surface of the developed tool did not detach in certain cutting conditions. Next, in order to generate a sharp edge on the CFRP and restrict the increase in the CFRP temperature with the cBN electroplated end-mill, the optimum abrasive size and grinding condition were investigated through the design of experiments. Moreover, the effectiveness of the developed tool was verified by comparing it with a conventional tool. As a result, smaller burrs and uncut fibers were observed after final machining with the developed tool under the derived optimum condition than those with conventional tools. However, the desired surface roughness could not be achieved as required by the airline industry. Therefore, oscillating grinding was applied. In addition, the formula of the theoretical surface roughness while using the developed tool was derived using the theory of slant grinding. As a result, the oscillating condition that led to the required surface roughness was obtained by theoretical analysis. In addition, the required value for the airline industry was achieved by oscillating grinding.

Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.


1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.


2011 ◽  
Vol 486 ◽  
pp. 91-94 ◽  
Author(s):  
Jabbar Abbas ◽  
Amin Al-Habaibeh ◽  
Dai Zhong Su

Surface roughness is one of the most significant parameters to determine quality of machined parts. Surface roughness is defined as a group of irregular waves in the surface, measured in micrometers (μm). Many investigations have been performed to verify the relationship between surface roughness and cutting parameters such as cutting speed, feed rate and depth of cut. To predict the surface produced by end milling, surface roughness models have been developed in this paper using the machining forces by assuming the end mill cutter as a cantilever beam rigidly or semi- rigidly supported by tool holder. An Aluminium workpiece and solid carbide end mill tools are used in this work. Model to predict surface roughness has been developed. Close relationship between machined surface roughness and roughness predicted using the measured forces signals.


2010 ◽  
Vol 154-155 ◽  
pp. 626-633
Author(s):  
Moola Mohan Reddy ◽  
Alexander Gorin ◽  
Khaled A. Abou-El-Hossein

The present experimental study aimed to examine the selected machining parameters on Surface roughness in the machining of alumina nitride ceramic. The influence of cutting speed and feed rate were determined in end milling by using Cubic boron nitride grinding tool. The predictive surface roughness model has been developed by response surface methodology. The response surface contours with respect to input parameters are presented with the help of Design expert software. The adequacy of the model was tested by ANOVA.


2013 ◽  
Vol 581 ◽  
pp. 247-254 ◽  
Author(s):  
Martin Novák ◽  
Natasa Naprstkova

Machining of tool steels is often an important used technology. Products made from these materials are often used in mechanical engineering, and quality of workpiece surface roughness after machining respective grinding is one of the important parameters that to us speak about the quality of the machining process. The paper deals with the influence of cutting conditions when grinding tool steel X38CrMoV5 (EN ISO) on machined surface roughness.


Author(s):  
Balla S Prasad ◽  
Chandra M KarakaVVNR ◽  
Venkata S Annavarapu

The investigation of surface roughness in machined materials/products has proven to be a difficult undertaking. The surface quality is determined not only by the parameters but also by the cutting conditions. Surprisingly, a study indicated that when analysing the quality of machining processes currently being done, surface morphology has a significant impact on tool performance. PCD (Polycrystalline diamond) and PCBN (Poly cubic boron nitride) cutting tools produce a better surface finish, which is explored in the machining of Al-Mg/Zr/TiO2 (15%), nano metal matrix composites (NMMC). The study primarily focuses on determining the best parameters for end milling NMMCs in tests for long-term production sustainability. Using scanning electron microscopy, microstructural study of the machined surface will aid in finding the parameters responsible for the cause of surface integrity. The work focusses on analysing tool performance by monitoring the machining process in real time using signal characteristics, forecasting vibrations (displacement) and machine outputs using surface topography and chip analysis. The tool failure was acquired by establishing a correlation between displacement (vibrations) and post machining outcome of experimental study, as a result, the evolution of displacement in the PCBN tool is 24.7 μm, which is better compared to 34.3 μm in the PCD tool at 3000 r/min. PCBN outperformed PCD with a 1.82 μm surface roughness, resulting in longer tool life. Thus, this economical reliable empirical method the problem of finding difficulty identifying the causing of tool wear and failure by correlating sensor signals features with experimental results.


2015 ◽  
Vol 22 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Erol Kiliçkap ◽  
Ahmet Yardimeden ◽  
Yahya Hışman Çelik

AbstractCarbon fiber-reinforced plastic (CFRP) composites are materials that are difficult to machine due to the anisotropic and heterogeneous properties of the material and poor surface quality, which can be seen during the machining process. The machining of these materials causes delamination and surface roughness owing to excessive cutting forces. This causes the material not to be used. The reduction of damage and surface roughness is an important aspect for product quality. Therefore, the experimental study carried out on milling of CFRP composite material is of great importance. End milling tests were performed at CNC milling vertical machining center. In the experiments, parameters considered for the end milling of CFRP were cutting speed, feed rate, and flute number of end mill. The results showed that damage, surface roughness, and cutting forces were affected by cutting parameters and flute number of end mill. The best machining conditions were achieved at low feed rate and four-flute end mill.


2009 ◽  
Vol 407-408 ◽  
pp. 714-717 ◽  
Author(s):  
Yoshio Mizugaki ◽  
Kazuki Takafuji ◽  
Koichi Kikkawa

This paper describes the cutting characteristics of aluminum alloys in dry end milling experimentally. The tested materials are A1050, A2017, A2024, A5025 and A7075. The cutter is a flat end mill of Co-cemented High Speed Steel with the diameter of 20 mm. Through the experimental results of side milling, the following three aspects have been found out. Firstly, as to the machining error, A1050 showed smaller machining error than 15 μm in the cutting speed rage from 62.8 m/min to 251.3 m/min. Other Aluminum alloys showed greater values. Secondly, as to the cutting force, those of aluminum alloys except A2017 were generally proportional to their material hardness. The cutting forces of A1050 and A5052 were constant over the whole range of cutting speed. Thirdly, as to the machined surface roughness, A7075 showed the smallest surface roughness among the all materials with its arithmetical mean roughness Ra under 0. 2 µm and with its maximum height of profile Rz under 1 μm. The machined surface roughness of A2017 varied widely. Through the visual inspection of machined surface, A2017 and A2024 showed picked surface as generated by a built-up edge. This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.


2016 ◽  
Vol 1136 ◽  
pp. 203-208
Author(s):  
Tatsuya Furuki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Kiyofumi Inaba ◽  
...  

In recent years, the demand for carbon fiber reinforced plastics (CFRP), which have excellent mechanical properties, is increasing in various fields. In particular, the amount of CFRP used accounts for more than 50% of the body structure weight of the state-of-the-art airplanes. Moreover, in such airplanes, stack material, which is a combination of CFRP and titanium alloy (Ti-alloy), is frequently used. Therefore, a novel high-efficiency end-milling technology for cutting CFRP and Ti-alloy simultaneously is required. It is known that for restraining the occurrence of tool wear, diamond coating, which has high hardness, is useful. On the other hand, in the case of machining of Ti-alloy, several problems arise due to the machining heat. Consequently, in this study, we focus on cBN (cubic boron nitride). In order to compare diamond coating and cBN, end-mills, which were electroplated diamond grains, were also fabricated. In this study, as a cutting experiment, side milling of stack material, which is a combination of CFRP and Ti-6Al-4V, was carried out using the fabricated tools. Then, we discuss their cutting performance by measuring the CFRP temperature and chip temperature, tool wear, surface roughness, and surface integrity. As a result, it could be expected to precisely cut the stack material with the fabricated electroplated cBN end-mill. However, it is seen that improvement of the tool shape or the electrodeposition process is required.


2016 ◽  
Vol 874 ◽  
pp. 463-468
Author(s):  
Tatsuya Furuki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Kiyofumi Inaba ◽  
...  

Currently, carbon fiber reinforced plastics (CFRP) are being increasingly adopted in various fields. Thus, machining CFRP with high accuracy and high efficiency is required. In addition, machining stack materials composed of CFRP and titanium alloys is required. Therefore, in this study, a novel end-mill electroplated with a cubic boron nitride (cBN) abrasive, which has high thermal resistance, is proposed. In order to evaluate the influence of the base metal shape of the proposed end-mill on the machining process, several cBN-electroplated end-mills with different rake angles or chamfers were fabricated and used to cut CFRP. In addition, in order to evaluate the abrasive shape, a blocky abrasive was also electroplated on the end-mill. The results indicate that the negative rake angle is useful to restrain the progression of tool wear. However, in order to obtain the element of cutting and grinding, it is required that the rake angle should be positive. Moreover, the reasonable width of chamfer is effective for restraining the increase in CFRP temperature. Further, a sharp shaped abrasive can more effectively generate a CFRP with a sharp edge compared with a blocky shape abrasive.


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